Samson MPL 1204 User Manual

MIXER

SAMSON

MPL 1204

Introduction 3

MPL 1204 Features 3

Guided Tour 5

Overview 5 Channels 6 Main Section 8 Rear Panel 11

Connecting The MPL 1204 - General Suggestions 13 Setting Up and Using the MPL 1204 15

Setting the Correct Gain Structure 16

Grounding Techniques 18 Busing, Submixing, and Channel Muting 19 Using Pan 20 Using Equalization 21 Using Aux Sends and Returns 22 Using Inserts 23 PFL/AFL Soloing 24 Applications Notes 25

Using The MPL 1204 As A Recording Mixer 25 Using The MPL 1204 As A Main Live Mixer 26 Using The MPL 1204 As A Keyboard Submixer 27 Linking The MPL 1204 With Other Mixers 28

Appendix A: Block Diagram 29 Specifications 30

Introduction / MPL 1204 Features

Congratulations on purchasing the Samson MPL 1204 four-bus microphone/line mixer! The MPL 1204 is optimized for use in both live performance and recording applications, and it can be used wherever there are a number of microphone or line-level sources that need to mixed down to two or four outputs. Although the MPL 1204 is designed for easy operation, we suggest you first take some time to go through these pages so you can fully understand how we’ve implemented a number of unique features.

In this manual, we’ll provide you with an overview of MPL 1204 features, followed by a guided tour of its front and rear panels. Then we’ll describe how the MPL 1204 should be connected to your existing equipment (including wiring diagrams) and talk about the important topics of gain structure and grounding techniques. Next, we’ll cover a number of specific MPL 1204 features (such as busing, submixing, channel muting, as well as using panning, equalization, auxiliary sends and returns, channel inserts, and PFL/AFL) in detail. Finally, we’ll wrap things up with a series of applications notes describing a number of ways to use the MPL 1204 for both recording and live performance, plus reference Appendices and full specifications. You’ll also find a warranty card enclosed—please don’t forget to fill it out and mail it so that you can receive online technical support and so we can send you updated information about other Samson products in the future.

SPECIAL NOTE: Should your unit ever require servicing, a

Return Authorization

number (RA) is necessary. Without this number, the unit will not be accepted. Please call Samson at 1-800-372-6766 for a Return Authorization number prior to shipping your unit. Please retain the original packing materials and, if possible, return the unit in its original carton and packing materials.

MPL 1204 Features

“MPL” stands for “Mic/Program/Line” and the name describes the broad range of signals which can be handled by this powerful four-bus mixer. In fact, the compact design of the MPL 1204 belies an extraordinary versatility. Add excellent sound quality to the equation, and you’ve got a product which is equally useful in live performance and for recording (you’ll find descriptions of each application at the conclusion of this manual). Here are some of the MPL 1204’s main features:

•Twelve independent channels, with both mic and line inputs for each channel. This allows you to blend together a variety of source signals, including dynamic or condenser microphones, keyboards, CD/tape players, etc. Standard XLR mic connectors (for microphone inputs) and electronically balanced 1/4" jacks (for line-level inputs) are provided for each channel; in addition, there is a dedicated stereo CD/Tape input that provides dual phono (RCA) jacks.

• Four

bus outputs (a “bus” is simply a pathway through which a signal can be routed) and an electronically balanced main stereo output, with dedicated front panel control. Any channel input can be routed to either of the two bus pairs (1/2 or 3/4), and any of the buses can be routed to the Left/Right mix output with the touch of a button. This flexible design allows you to easily mute selected channels and/or to create submixes within your main mix.

MPL 1204 Features

• Electronically balanced XLR Main stereo outputs as well as an independent electronically balanced stereo Control Room output (with dedicated level control) for connection to a power amplifier and studio monitors.

• A phantom power switch enables you to use the MPL 1204 with high-quality condenser microphones. When turned on, 48 volts of phantom power is provided to the mic connectors of all twelve input channels.

• Two auxiliary sends and two stereo auxiliary returns (which can be routed to any of the four buses). Aux send 1 is pre-fader and post-equalizer, while Aux send 2 is post-fader and post-equalizer.

• Independent 3-band equalization for each channel, with 15 dB of cut or boost for low (100 Hz) and high (10 kHz) frequencies, and 12 dB of cut or boost for mid (1 kHz) frequencies.

• Constant level Pan controls for each channel that allow you to precisely place each input signal in the left-right plane.

• Center detents for all Pan and EQ controls, making it easy to use the MPL 1204 even in low-light situations such as live performance.

• Selectable

Pre Fade Listen (PFL) or After Fade Listen (AFL) soloing for each channel. PFL allows headphone monitoring of individual channels, pre-fader (but post-EQ), while AFL enables headphone monitoring of individual channels, post-fader and post-EQ. Both types of solo function are non-mix-destructive in that they do not affect the signal being output either by the Main, Bus, or Control Room outputs.

• A flexible front panel metering system includes a ten-segment level meter and allows you to view at a glance the levels of the main Left/Right output, as well as main power, phantom power, and PFL or AFL status.

• An independent front-panel headphone output with dedicated volume control for private monitoring of soloed channels.

• Channel inserts for all twelve channels, enabling you to use outboard signal processors such as equalizers, compressor/ limiters, or noise gates in a standard “effect loop.”

• Bus inserts allow external signals to be submixed into any or all of the four buses and also enables linking of multiple mixers.

• The MPL 1204 can be mounted in any standard 19" rack (taking four rack spaces), making it easy to integrate into any existing system.

• Last but certainly not least, affordability. The MPL 1204 has been designed from the ground up to provide versatility and excellent sound quality at a cost-conscious price.

Guided Tour - Overview

The following illustration shows an overview of the front panel of the MPL 1204:

CH 1 CH 2

TRIM

+24

-30

-50

+24

HIGH

+15

-15 MID

MID

+12

-12

LOW

+15

-15 AUX 1

AUX 1

PRE

+10

∞

AUX 2

POST

+10

∞

SOLO

ON OFF

MUTE

3/4

PAN

+10

∞

LEVEL LEVEL LEVEL LEVEL LEVEL LEVEL LEVEL LEVEL LEVEL LEVEL LEVEL LEVEL

CH 3

TRIM

+24 HIGH

MID

LOW

AUX 1

AUX 2

SOLO

ON OFF

MUTE

3/4

TRIM

-30

-50

+24 HIGH

+15

-15 MID

+12

-12

LOW

+15

-15 AUX 1

PRE

+10

∞

AUX 2

POST

+10

∞

SOLO

ON OFF

MUTE

3/4

PAN

+10

∞

-30

-50

+15

-15 0

+12

-12

+15

-15

PRE

+10

∞

POST

+10

∞

3/4

PAN

+10

∞

CH 5 CH 6 CH 7 CH 8 CH 9 CH 10 CH 11 CH 12

CH 4

TRIM

+24 HIGH

MID

LOW

AUX 1

AUX 2

SOLO

ON OFF

MUTE

3/4

TRIM

-30

-50

+24 HIGH

+15

-15

MID

+12

-12

LOW

+15

-15

AUX 1

PRE

+10

∞

AUX 2

POST

+10

∞

SOLO

ON OFF

MUTE

3/4

PAN

+10

∞

POST

-30

+24 HIGH

+15

MID

+12

LOW

+15

AUX 1

PRE

+10

AUX 2

+10

SOLO

ON OFF

MUTE

+10

-30

-50

+24 HIGH

+15

-15

MID

+12

-12

LOW

+15

-15

AUX 1

PRE

+10

∞

AUX 2

POST

+10

∞

SOLO

ON OFF

MUTE

3/4

PAN

+10

∞

-50

-15 0

-12

-15

∞

PAN

∞

+15

+12

+15

+10

POST

+10

-30

-50

+24 HIGH

+15

-15

MID

+12

-12

LOW

+15

-15

AUX 1

PRE

+10

∞

AUX 2

POST

+10

∞

SOLO

ON OFF

MUTE

3/4

PAN

+10

∞

-50

PAN

TRIM

-30

-50

+24 HIGH

+15

-15

MID

+12

-12

LOW

+15

-15

AUX 1

PRE

+10

∞

AUX 2

POST

+10

∞

SOLO

ON OFF

MUTE

3/4

PAN

+10

∞

TRIM

-30

-50

+24 HIGH

+15

-15

MID

+12

-12

LOW

+15

-15

AUX 1

PRE

+10

∞

AUX 2

POST

+10

∞

SOLO

ON OFF

MUTE

3/4

PAN

+10

∞

CHANNELS MAIN SECTION

+15

+12

+10 POST

+10

AUX RETURNS

STEREO

TRIM

MID

LOW

AUX 1

SOLO

ON OFF

MUTE

3/4

∞

-30

-50

AUX RET.1/2

MUTE

3/4

+15

-15 0

L BALANCE

+12

-12

∞

AUX RET.3/4

+15

-15

PRE

MUTE

3/4

+10

∞

POST

BALANCE

+10

∞

PAN

+10

∞

PHONES

-30

+24 HIGH

+15

PRE

AUX 2

+10

-20

LEFT

RIGHT

-20

PFL

SOLO

+10

+10 dB

+10

∞

SAMSON

MPL 1204 MIC MIXER

-9 -6 -3

-15

0+2+4+6

-9 -6 -3

-15

0+2+4+6

POWER

PHANTOM

AFL

PHANTOM METER TAPE PFL AFL

∞

MAIN LEVEL

+10

CONTROL ROOM

BUS 2BUS 1 BUS 3

1-2 3-4

∞

BUS 4

11/12

+10

+10 dB

∞

Guided Tour - Channels

1: Trim (black) - This knob determines the input level of the connected signal. Continuously adjustable from +4 dB to -50 dB (for mic inputs) or +24 to -30 dB (for line inputs), the input signal is boosted when the trim is turned clockwise and attenuated when turned counterclockwise. For information on how to properly set this for each channel, see the section on page 14 entitled “Setting The Correct Gain Structure.”

2: Equalizer (violet) - These knobs determine the amount of boost or attenuation in each of three frequency areas (up to 15 dB for low and high frequencies, and up to 12 dB for the mid frequency). The mid frequency control (centered at 1 kHz) utilizes a resonant (“bell”) peaking curve, while the high and low frequency controls (centered at 10 kHz and 100 Hz, respectively) utilize shelving curves. A center detent in each knob (at the “0” position) indicates no boost or attenuation (that is, flat response). As each knob is turned clockwise from the “0” position, the frequency area is boosted; as it is turned counterclockwise from the “0” position, the frequency area is attenuated. For more information on the application of EQ, see the “Using Equalization” section on page 19 in this manual.

3: Auxiliary sends (blue) - These knobs allow you to route signal to either or both of the MPL 1204’s two monophonic Auxiliary outputs. These are typically used to create submixes (for example, a headphone cue mix) and to feed signal from single or multiple channels to outboard effects devices. At the “0” (2 o’clock) position, the signal is routed with unity gain (that is, no boost or attenuation). As each knob is turned clockwise from the “0” position, the signal is boosted; as it is turned counterclockwise from the “0” position, it is attenuated. Aux send 1 is post-eq but

pre-fade; that is, the level of the signal is determined solely by its Trim control and its EQ settings (see #1 and #2 above). In contrast, Aux send 2 is post-eq and

post-fade; that is, the level of the signal is determined by the channel’s Trim control, its EQ settings, and the position of its Level control. For more information, see the “Using Aux Sends and Returns” section on page 20 in this manual.

4: Solo On/Off switch - When pressed in, the channel is soloed (in headphones only). Soloing will be in either PFL (Pre Fade Listen) or AFL (After Fade Listen) mode, depending upon the setting of the PFL/AFL switch in the MPL 1204 main section. See #7 and #8 on page 7 and the “PFL/AFL Soloing” section on page 22 in this manual for more information.

5: Mute 3/4 switch - When up, the channel’s signal is routed to the Bus 1/2 faders and then on to the Bus 1/2 and, optionally, Main and Control Room output jacks (if, as described in #14 on page 8, the Bus “L/R” switches for those buses is pressed in). When pressed in, the channel’s signal is instead routed to the Bus 3/4 faders and then on to the Bus 3/4 and, optionally, Main and Control Room output jacks (if, as described in #14 on page 8, the Bus “L/R” switches for those buses is pressed in). If you set the Bus 3/4 faders all the way down (to their “∞” position), this switch can be used for channel muting. See the “Busing, Submixing and Channel Muting” section on page 17 in this manual for more information.

6: Pan (green) - This knob allows you to place the input signal anywhere in the left-right stereo spectrum, while keeping the overall signal level constant. When the knob is placed at its center (detented) position, the signal is sent equally to both left and right outputs of the selected bus (depending upon the setting of the channel’s Mute 3/4 switch, as described in #5 above). When moved left of center, less signal is sent to the right output and more signal is sent to the left output (making the sound appear left of center) and when moved right of center, less signal is sent to the left output and more signal is sent to the right output (making the sound appear right of center). To route a signal hard left or right, place the pan knob either fully counterclockwise or fully clockwise. For more information, see the “Using Pan” section on page 18 in this manual.

CH 1

TRIM

+24

HIGH

-15

MID

-12

LOW

-30

-50

+15

+12

-15

AUX 1

∞

AUX 2

∞

SOLO

ON OFF

MUTE

3/4

∞

PAN

LEVEL

+15

PRE

+10

POST

+10

Guided Tour - Channels

7: Level (white) - This knob (purposely made a little bigger than the others so you can find it easily in low-light situations) controls the volume of the channel input. In practice, you will use the Level controls to continuously adjust the loudnesses of the various signals being blended together by the MPL 1204. The “0” (2 o’clock) position of the knob indicates unity gain (no level attenuation or boost). Moving the knob counterclockwise from the “0” position (towards “∞”) causes the signal to be attenuated (at the very bottom, it is attenuated infinitely— in other words, there is no sound). Moving it clockwise from the “0” position (towards “+10”) causes the signal to be boosted by as much as 10 dB.

For best signal-to-noise ratio, all Level controls for channels carrying signal should generally be kept at or near the “0” position. Channels that are unused should have their Level controls kept fully counterclockwise at their “∞” (minimum) level. See the “Setting the Correct Gain Structure” section on page 14 in this manual for more information.

Guided Tour - Main Section

1: Auxiliary Return Level (orange) - These knobs determine the input level of signal arriving via the MPL 1204’s two stereo Auxiliary returns. The “0” (2 o’clock) position of each knob indicates unity gain (no level attenuation or boost). Moving each knob counterclockwise from the “0” position (towards “∞”) causes the signal to be attenuated (at the fully counterclockwise position, it is attenuated infinitely—in other words, there is no sound). Moving each knob clockwise from the “0” position (towards “+10”) causes the signal to be boosted by as much as 10 dB. For information on how to properly set these, see the sections in this manual entitled “Setting the Correct Gain Structure” and “Using the Aux Sends and Returns” (pages 14 and 20).

2: Stereo Auxiliary Return Bus switch - These switches determine which of the two pairs of stereo buses (1/2 or 3/4) the Aux return signal is routed to. When up, the Return’s signal is routed to the Bus 1/2 faders and then on to the Bus 1/2 jacks as well as (if the Bus “L/R” switch is pressed in—see #14 on page

8) the Main and Control Room output jacks. When pressed in, the channel’s signal is instead routed to the Bus 3/4 faders and then on to the Bus 3/4 jacks as well as (if the Bus “L/R” switch is pressed in) the Main and Control Room output jacks. If you set the Bus 3/4 faders all the way down (to their “∞” position), this switch can be used for selective muting of Aux returns. For more information, see the sections in this manual entitled “Busing, Submixing and Channel Muting” and “Using the Aux Sends and Returns” (pages 17 and 20).

AUX RETURNS

STEREO

∞

AUX RET.1/2

MUTE

3/4

BALANCE

∞

AUX RET.3/4

MUTE

3/4

L BALANCE

+10

SAMSON

MPL 1204 MIC MIXER

-20

-9 -6 -3

-15

LEFT

RIGHT

-20

-9 -6 -3

-15

PFL

PHANTOM METER TAPE

SOLO

PFL AFL

∞

MAIN LEVEL

+10

0+2+4+6

PHANTOM

AFL POWER

1-2 3-4

+10

∞

CONTROL ROOM

11/12

+10 dB

6 7 8

9 10 11 12 13 14

4 5

∞

PHONES

+10

∞

BUS 2BUS 1 BUS 3

∞

BUS 4

Guided Tour - Main Section

3: Stereo Auxiliary Return Balance (brown) - These knobs determine the relative levels of the left and right input signals connected to the MPL 1204’s two stereo Auxiliary returns. When the knob is placed at its center (detented) position, both left and right input signals for that Aux return are at equal strength. When moved left of center, the left input signal remains at the same strength but the right input signal is attenuated; when the knob is moved right of center, the right input signal remains at the same strength but the left input signal is attenuated. When placed fully counterclockwise, only the left input signal is heard (panned hard left); when placed fully clockwise, only the right input signal is heard (panned hard right). These “radical” positions are useful when you are using a stereo Aux return as two mono returns—see the “Using Aux Sends and Returns” section on page 20 in this manual for more information.

4: Headphone Level - This knob sets the level of the signal sent to the headphone jack (see #5 below). WARNING: To avoid possible damage to connected headphones (or, worse yet, to your ears!), always turn this all the way off (to the fully counterclockwise “0” position) before plugging in a pair of headphones—then raise the level

slowly while listening. The Headphone Level

has no effect on the final Main output level or on the Control Room output level. 5: Headphone jack - Connect any standard stereo headphones to this jack

(via a 1/4" TRS plug) for private monitoring of all soloed channels. The built-in MPL 1204 headphone preamp delivers 120 mw at 33 ohms. For more information, see the “PFL/AFL Soloing” section on page 22 in this manual.

6: Meter - This ten-segment bar meter shows the continuous output level of either Bus 1/2 or Bus 3/4, depending upon the setting of the Meter switch (see # 10 on page 8). For optimum signal-to-noise ratio, try to adjust all channel levels so that program material is usually at or around 0 VU, with occasional but not steady excursions to the red “+” segments. See the “Setting the Correct Gain Structure” section on page 14 in this manual for more information.

7: Status LEDs - These show the status of various conditions within the MPL 1204. The leftmost LED (labeled “PFL”) lights steadily green when the MPL 1204 is in PFL mode (see #8 below). The left center LED (labeled “AFL”) lights steadily red when the MPL 1204 is in AFL mode (see #8 below). The right center LED lights steadily green when the Phantom Power switch (see #9 below) is engaged and 48 volts phantom power is being delivered to all XLR mic connectors. The rightmost LED (labeled “Power”) lights steadily red whenever the MPL 1204 is powered on.

8: Solo switch - This determines whether the MPL 1204 is in PFL mode (switch up) or AFL mode (switch pressed in). For more information, see the “PFL/AFL Soloing” section on page 22 in this manual.

9: Phantom Power switch - When this switch is pressed in, the MPL 1204 delivers 48 volts of phantom power to pins 2 and 3 of all XLR microphone connectors in all twelve channels. WARNING: Only use this switch with the MPL 1204 powered down. Before turning phantom power on, be sure to disconnect all non-microphone signal sources (such as passive direct injection boxes) from the XLR mic jacks. Although phantom power will have no adverse affect on connected dynamic microphones, it should be used only when one or more condenser microphones are connected to the MPL 1204.

Refer to the owners manual of your microphone to determine whether or not it requires 48 volts phantom power—we cannot assume responsibility if you damage a mic by incorrectly applying phantom power. If you’re not completely

Guided Tour - Main Section

certain that one or more connected mics require 48 volts phantom power, leave this switch off (its out position).

10: Meter switch - When out, the ten-segment MPL 1204 meter (see #6 on the previous page) shows the continuous output level of Bus 1-2; when pressed in, the meter shows the continuous output level of Bus 3-4.

11: Tape switch - Press this in to route signal connected to the rear panel RCA jack tape inputs to channels 11 and 12 (the left side is routed to channel 11 and the right side is routed to channel 12). When this switch is pressed in, any mic or line input signal connected to channels 11 and 12 is automatically muted.

12: Main Level - This knob determines the final signal level of the rear panel Main output—you can think of it as being the “master fader.” The 2 o’clock “0” position of the knob indicates unity gain (no level attenuation or boost). Moving the knob counterclockwise from the “0” position (towards “∞”) causes the signal to be attenuated (at the very bottom, it is attenuated infinitely—in other words, there is no sound). Moving it clockwise from the “0” position (towards “+10”) causes the signal to be boosted by up to 10 dB. For more information, see the “Setting The Correct Gain Structure” section on page 14 in this manual.

13: Control Room Level - This knob determines the signal level of the rear panel Control Room output, allowing independent monitoring of the Main output signal. The 2 o’clock “0” position of the knob indicates unity gain (no level attenuation or boost). Moving the knob counterclockwise from the “0” position (towards “∞”) causes the signal to be attenuated (at the very bottom, it is attenuated infinitely—in other words, there is no sound). Moving it clockwise from the “0” position (towards “+10”) causes the signal to be boosted by up to 10 dB.

14: Bus L/R switches - These switches allow you to route the output from the four buses to the Main left/right output jacks and Control Room left/right output jacks on the rear panel (see #10 and #11 on page 10). When this switch is up, the signal from that bus is not routed to the main outputs and instead terminates at its Bus out jack (see #12 on page 10). When pressed in, the signal from that bus is routed to the Main and Control Room outputs (buses 1 and 3 are routed to the left Main and Control Room output jacks and buses 2 and 4 are routed to the right Main and Control Room output jacks) as well as to its Bus out jack. For more information, see the “Busing, Submixing and Channel Muting” section on page 17 in this manual.

15: Bus Faders (white with blue line) - These linear sliders determine the relative level of the four bus outputs. The “0” position of each fader indicates unity gain (no level boost or attenuation). Moving the fader below this position (towards the “∞” position) causes the signal to be attenuated (at the very bottom, it is attenuated infinitely—in other words, there is no sound). Moving it above this position (towards the “+10 dB” position) causes the signal to be boosted by up to 10 dB. For best signal-to-noise ratio, all Bus faders should generally be kept at or near the 0 level. For more information, see the “Setting The Correct Gain Structure” and the “Busing, Submixing and Channel Muting” sections on pages 14 and 17 in this manual.

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